An alternative approach for coordination is to use the idea of zero-forcing (ZF) [1]}, [2]}. In this approach, the PS ignores noise in the channel and coordinates the devices, such that the noise-free version of the estimated global model constructs the desired global model. From (REF ), this means that the PS finds \(\mathbf {m}\)  and \(\left\lbrace b_\ell  \right\rbrace \) , such that
\(\mathbf {m}^\mathsf {T}\mathbf {h}_\ell b_\ell = \phi _\ell .\) 
